Expansion joints (also known as compensators) may be used in a pipe system to absorb axial, lateral and angular movements between pipes in the pipe system. In particular, expansion joints may be used to accommodate movement of the pipes due to thermal expansion of the pipes. One type of expansion joint, called a single unrestrained bellows expansion joint, consists of a bellows secured between two adjacent pipe sections. The bellows includes one or more convolutions to allow for bending or deflection of the joint. The expansion joint does not include any mechanism that contains or absorbs internal pressure thrust in the pipe system. That is, the single unrestrained bellows expansion joint does not include a mechanism or component that provides tensile support to prevent the expansion joint from pulling apart at the bellows due to internal pressure thrust.
Some other types of expansion joints include mechanisms that contain or absorb internal pressure thrust in the pipe system while allowing for limited angular movement or bending. A single hinged bellows expansion joint includes an external hinge or pivot that allows for angular movement in only one plane while absorbing internal pressure thrust. That is, the single hinged bellows expansion joint allows for single-directional movement while providing tensile support to prevent the expansion joint from pulling apart at the bellows due to internal pressure thrust. A gimbaled bellows expansion joint includes two external hinges that allow for angular movement in two planes while absorbing internal pressure thrust.